The present invention relates to dense wavelength division multiplexed systems, and more particularly to gain equalization in dense wavelength division multiplexed systems.
Fiber optic networks are becoming increasingly popular for data transmission due to their high speed, high capacity capabilities. In conventional wavelength division multiplexed (WDM) fiber optic networks, signals travel along optical fibers toward a destination node. Occasionally, the signals must be amplified by an optical amplifier, such as an Erbium Doped Fiber Amplifier (EDFA), due to attenuation of the signal strength.
The power level of digital or analog data transmissions over any given segment of the WDM network will generally vary over time. With increasing network complexity, rapid or short-term power fluctuations in signal levels are becoming of increasing concern. Such fluctuations may be caused by fluctuations in the number of data channels carried by the network and variability of the routing of the various signal channels prior to their arrival at that segment. Furthermore, both the total gain and the average gain per channel provided by an optical amplifier may depend upon the number of channels carried by the network at the point of the amplifier. This latter quantity can vary virtually instantaneously in the network depending upon network traffic conditions and routing configurations. For the above reasons, the total power level can fluctuate rapidly within a segment of a complex WDM network.
Accordingly, there is a need for a method and system for dynamic gain attenuation. The present invention addresses such a need.
A dynamic gain equalizer (DGE) includes: a mirror; an electrode; and a lever with a first end and a second end opposite to the first end, where the lever is capable of rotating about a fulcrum, where the lever rotates the first end toward the electrode when the electrode is charged such that the second end blocks a portion of a channel from reaching the mirror, where an unblocked portion of the channel is reflected by the mirror. By manipulating the charge on the electrode, the rotation of the lever is controlled, determining how much of the light is blocked by the lever. Each lever in an array can attenuate a channel or a group of channels of a composite optical signal by a different amount. The DGE provides a significant range of blockage and can be closely spaced. It provides ease in integrating channel monitoring into the DGE.